A need exists for a method to rapidly detect bacteria in urine and various other fluid samples.
Urine specimens are the major work load of the diagnostic laboratory. The most common urological disease is urinary-tract infections in children, pregnant women, diabetics and geriatric patients, (bacteriuria). In hospitals, bacteriuria is the predominant form of nosocomial infection. In view of the frequent asymptomatic urinary-tract infections bacteriuria tests must be sufficiently simple and economical to permit routine testing. A need, therefore, exists for simple, rapid, inexpensive screening tests to facilitate diagnosis and ensure prompt treatment of bacteriuric patients.
The conventional method for detection of urinary-tract infections is by inoculation of urine onto agar culture plates and incubation of these plates at optimal temperatures (usually 37 degrees C.) for 24-48 hours; bacteria are detected by formation of colonies on the agar surface. Fastidious bacteria may not grow on conventional culture media, and a variety of agar media may be required to detect these bacteria. This procedure is time consuming and expensive.
Although staining techniques, such as the Gram Stain Method, are known in clinical microbiology light microscopy is required, and the procedures are time consuming and require a skilled microbiologist. Other prior art processes involve staining of bacteria followed by concentration by centrifugation or filtration. These processes require chelating agents and positively-charged small pore filters, and suffer clogging and interference from anionic pigments, blood and other substances which may be present in urine.
It has now been unexpectedly discovered that both gram negative and gram positive bacteria can be stained for simple, rapid detection by means of the composition of the present invention. Concentrated bacteria stained with the composition described herein are readily visible and can thus be rapidly detected without resorting to light microscopic examination by specially trained personnel, or the use of expensive, perishable agar cultures. The present invention allows the efficient detection of bacteria while reducing clogging and pigment interference common to prior art methods. Furthermore, it was discovered through tests that inexpensive, simple, and rapid quantitative analysis of bacteria is possible employing the present staining composition.